JP2020200718A - Revolving control device for construction machine - Google Patents

Abstract

To provide a revolving control device for construction machines that can reduce timing variations depending on work types for generating hydraulic braking for a revolving motor, even if deceleration operation is started at the time when the revolving speed does not reach the maximum speed with respect to the operation amount of a revolving operation lever.SOLUTION: The revolving control device for construction machines comprises: a pilot pressure calculation unit 92 that calculates, based on a revolving speed, braking pilot pressure for generating hydraulic braking for a revolving motor; a deceleration operation determination unit 91 that determines whether a revolving operation member 31 has received deceleration operation that is operation for reducing the revolving speed; and a decompression signal input unit 93 that inputs, to a decompression valve 50A or 50B, a decompression command signal for decompressing pilot pressure output from a revolving pilot valve 32 to the braking pilot pressure when the deceleration operation determination unit 91 determines that the revolving operation member 31 has received the deceleration operation.SELECTED DRAWING: Figure 3

Description

The present invention relates to a swivel control device for a construction machine including an upper swivel body that can swivel with respect to a substrate.

As a turning control device for construction machinery, Patent Document 1 discloses a hydraulic actuator operation structure. The pilot valve in the hydraulic actuator operation structure is provided with a potentiometer for detecting the position of the spool corresponding to the angle of the operation lever. When the operating lever is tilted to rotate the swivel table, a signal from the potentiometer regarding the position of the spool is input to the control device. Then, an operation signal is issued from the control device to the electromagnetic proportional pressure reducing valve so that the larger the tilt angle of the operation lever is, the larger the flow rate to the direction switching valve is, whereby the swivel table performs a swivel operation. That is, in the hydraulic actuator operation structure of Patent Document 1, the opening degree of the electromagnetic proportional pressure reducing valve is adjusted according to the operation amount of the operation lever (the tilt angle of the operation lever).

By the way, in the actual work site of a construction machine, when the upper swivel body is swiveled, when the swivel speed of the upper swivel body does not reach the maximum speed corresponding to the operation amount of the swivel operation lever, the upper swivel body Often a deceleration operation is started to reduce the turning speed.

Japanese Unexamined Patent Publication No. 2-261905

However, if the deceleration operation is started when the turning speed does not reach the maximum speed corresponding to the operation amount of the turning operation lever, the turning speed at the time when the deceleration operation is started differs for each work. In this case, in the hydraulic actuator operation structure of Patent Document 1, since the opening degree of the electromagnetic proportional pressure reducing valve is adjusted according to the operation amount of the operation lever, the timing at which the hydraulic braking action occurs in the swing motor is set for each operation. It will vary according to the different turning speeds. This makes it difficult to stop the turning motion of the upper swing body at an appropriate turning angle to accurately move the attachment to the target position, and extra work is required to correct the position of the attachment.

Further, in Patent Document 1, when the operating lever is operated from the state where the operating lever is operated near the maximum speed position to the neutral stop position, the spool of the electromagnetic proportional pressure reducing valve is quickly slid to the minimum opening A1. It is disclosed that. This minimum opening degree A1 is the minimum opening degree in the range of the opening degree of the spool that brings about the maximum flow rate. That is, the technique disclosed in Patent Document 1 increases the operating speed of the spool near the maximum speed at which the flow rate does not change, and does not solve the above problem.

An object of the present invention is that even if the deceleration operation is started when the turning speed does not reach the maximum speed corresponding to the operation amount of the turning operation lever, the timing at which the hydraulic braking action is generated in the turning motor is set for each work. The purpose is to provide a turning control device for construction machinery that can suppress the variation.

Provided by the present invention is a swivel control device for a construction machine provided with an upper swivel body that can swivel with respect to a substrate, a hydraulic pump that discharges hydraulic oil, and the hydraulic oil that is discharged from the hydraulic pump. A swivel motor that operates to swivel the upper swivel body in response to the supply of the above, a swivel operation member that receives a swivel operation that is an operation for operating the swivel motor, and a pilot pressure according to the operation amount of the swivel operation. A swivel operation device having a swivel pilot valve that outputs A swivel control valve that opens and closes to change the size of the opening on the meter-out side, a swivel speed detection unit that detects the swivel speed of the upper swivel body, and the upper swivel body swivels at the swivel speed. The braking action pilot pressure for causing the hydraulic braking action in the turning motor while the motor is operating, and the braking action pilot pressure for adjusting the size of the opening on the meter-out side so that the hydraulic braking action is generated. , A pilot pressure calculation unit that calculates based on the turning speed, a deceleration operation determination unit that determines whether or not the turning operation member has received a deceleration operation that is an operation for reducing the turning speed, and the turning pilot. A pressure reducing valve interposed between the valve and the turning control valve, and the pilot pressure output from the turning pilot valve is converted into a pilot pressure corresponding to the pressure reducing command signal by receiving an input of the pressure reducing command signal. A pressure reducing valve capable of depressurizing and inputting to the swivel control valve, and an output from the swivel pilot valve when the deceleration operation determination unit determines that the swivel operation member has undergone the deceleration operation. It is provided with a pressure reducing signal input unit for inputting the pressure reducing command signal to the pressure reducing valve so as to reduce the pilot pressure to the braking action pilot pressure.

In this swivel control device, when it is determined that the swivel operation member has undergone the deceleration operation (hereinafter, may be referred to as "deceleration determination"), the decompression command signal is input to the decompression valve. As a result, the pilot pressure output from the turning pilot valve is reduced to the braking action pilot pressure, and the braking action pilot pressure is input to the turning control valve. As a result, even if the deceleration operation is started when the turning speed does not reach the maximum speed corresponding to the operating amount of the turning operation lever, the timing at which the hydraulic braking action is generated in the turning motor varies from work to work. Can be suppressed. Specifically, it is as follows.

The size of the opening on the meter-out side of the swivel control valve increases or decreases according to the pilot pressure output from the swivel pilot valve, and the pilot pressure increases or decreases according to the amount of operation of the swivel operating member. .. Therefore, the size of the opening on the meter-out side increases or decreases according to the amount of operation of the turning operation member. Further, the flow rate of the hydraulic oil on the meter-out side increases or decreases according to the turning speed. In order to generate the hydraulic braking action in the swing motor, the back pressure on the meter-out side needs to be increased, and in order to increase the back pressure, the flow rate of the hydraulic oil on the meter-out side is increased. The opening on the meter-out side needs to be narrowed down to an appropriate size. Specifically, when the turning speed at the time when the deceleration operation is started is large (for example, when the turning speed at the time when the deceleration operation is started is close to the maximum speed corresponding to the operation amount of the turning operation lever). The flow rate of the hydraulic oil on the meter-out side is also large. In this case, even if the opening on the meter-out side is relatively large, the back pressure on the meter-out side increases, and the hydraulic braking action is likely to occur. On the other hand, when the turning speed at the time when the deceleration operation is started is small (for example, the turning speed at the time when the deceleration operation is started is smaller than the maximum speed corresponding to the operation amount of the turning operation lever, and the turning speed is concerned. When the difference between the maximum speed and the maximum speed is large), the flow rate of the hydraulic oil on the meter-out side is also small. In this case, in order to increase the back pressure on the meter-out side and cause the hydraulic braking action, it is necessary to reduce the size of the opening on the meter-out side to a relatively small size.

Therefore, in the present invention, at the time of the deceleration determination, the pressure reducing command signal is input to the pressure reducing valve, whereby the pilot pressure output from the turning pilot valve is reduced to the braking action pilot pressure, and the braking action is performed. A configuration is adopted in which the pilot pressure is input to the swivel control valve. The braking action pilot pressure forcibly adjusts the opening on the meter-out side of the turning control valve to a size corresponding to the turning speed at the time of the deceleration determination so that the hydraulic braking action is quickly generated in the turning motor. It is a pilot pressure for the engine, and is calculated based on the turning speed at the time of the deceleration determination. Therefore, in the present invention, regardless of the turning speed at the time of the deceleration determination, the size of the opening on the meter-out side of the turning control valve is quickly set to a size such that the hydraulic braking action is quickly generated in the turning motor. Can be adjusted to. This is a case where the deceleration operation is started when the turning speed does not reach the maximum speed corresponding to the operation amount of the turning operation lever, and the turning speed at the time when the deceleration operation is started differs for each work. Even in such a case, it is possible to suppress the timing at which the hydraulic braking action occurs in the swivel motor from varying from work to work.

The swivel control device of the construction machine further includes a pilot pressure detection unit that detects the pilot pressure output from the swivel pilot valve, and the deceleration operation determination unit is the pilot pressure detected by the pilot pressure detection unit. When is less than the preset pilot pressure threshold value, it may be determined that the turning operation member has undergone the deceleration operation.

In this aspect, the timing at which the hydraulic braking action is generated in the turning motor, that is, the position of the turning operation lever at which the brake starts to work is uniformly set based on the pilot pressure threshold value. This makes it possible for the brake to start working at the same lever position corresponding to the pilot pressure threshold, regardless of the turning speed at the time the deceleration operation is started. As a result, the workability of the turning work is further improved.

The swivel control device of the construction machine further includes a pilot pressure detection unit that detects the pilot pressure output from the swivel pilot valve, and the deceleration operation determination unit is the pilot pressure detected by the pilot pressure detection unit. Is equal to or higher than the preset first pilot pressure threshold value, and then the pilot pressure detected by the pilot pressure detection unit is a preset second pilot pressure threshold value, which is the first pilot pressure threshold value. When it becomes less than the second pilot pressure threshold value smaller than, it is preferable to determine that the turning operation member has undergone the deceleration operation.

In this aspect, the timing at which the hydraulic braking action is generated in the swivel motor, that is, the position of the swivel operation lever at which the brake starts to work is uniformly set based on the second pilot pressure threshold value. This makes it possible for the brake to start working at the same lever position corresponding to the second pilot pressure threshold, regardless of the turning speed at the time when the deceleration operation is started. As a result, the workability of the turning work is further improved. Further, in this embodiment, after the turning operation member is operated more than the operation amount corresponding to the first pilot pressure threshold value, the turning operation member is operated less than the operation amount corresponding to the second pilot pressure threshold value. Only when this is done, control is performed to input the reduced braking action pilot pressure to the turning control valve. Therefore, it is more strictly determined whether or not the turning operation member has received the deceleration operation.

As described above, according to the present invention, even when the deceleration operation is started when the turning speed of the upper turning body does not reach the maximum speed corresponding to the operation amount of the turning operation lever, the swing motor It is possible to prevent the timing of causing the hydraulic braking action from varying from work to work.

It is a side view which shows the construction machine provided with the turning control device which concerns on embodiment of this invention. It is a figure which shows the hydraulic circuit of the turning control device. It is a block diagram which shows the functional structure of the controller in the turning control device, and the input / output signal thereof. It is a graph which shows the time-dependent change of the pilot pressure output from the swing pilot valve of the swing control device, and the time-dependent change of the swing speed of the upper swing body in the construction machine. The turning speed of the upper turning body and the turning control valve of the turning control device capable of causing a hydraulic braking action in the turning motor of the turning control device when the upper turning body is turning at the turning speed. It is a map showing the relationship with the size of the opening on the meter-out side. It is a graph which shows the relationship between the size of the opening on the meter-out side, and the target secondary pressure in the pressure reducing valve of the swing control device. It is a graph which shows the relationship between the target secondary pressure in the pressure reducing valve, and the pressure reduction command signal (instruction current) which should be input to the pressure reducing valve in order to adjust the secondary pressure in the pressure reducing valve to the target secondary pressure. .. It is a flowchart which shows the arithmetic control operation of the controller in the turning control device.

Preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a construction machine equipped with a turning control device according to this embodiment. The construction machine 100 is a hydraulic excavator, and is a crawler type lower traveling body 1 (an example of a substrate) and a lower traveling body 1 so as to be able to turn around a turning center axis Z perpendicular to the running surface thereof. It includes an upper swivel body 2 mounted on the top and an attachment 3 mounted on the upper swivel body 2. The attachment 3 is rotatably connected to a boom 4 undulatingly supported by the upper swing body 2, an arm 5 rotatably connected to the tip of the boom 4, and a tip of the arm 5. Tip attachment 6 and the like. In the present embodiment, the tip attachment 6 is a bucket.

The construction machine 100 includes a boom cylinder 7 that operates so as to cause the boom 4 to undulate with respect to the upper swing body 2, and an arm cylinder that operates to rotate the arm 5 with respect to the boom 4. 8 and a tip attachment cylinder 9 that operates so as to rotate the tip attachment 6 with respect to the arm 5.

FIG. 2 is a diagram showing a hydraulic circuit of the turning control device. As shown in FIG. 2, the swivel control device includes a hydraulic pump 10, a pilot pump 11, a swivel motor 20, a swivel operation device 30, a swivel control valve 40, a first pressure reducing valve 50A, and a second pressure reducing valve 50A. It includes a pressure reducing valve 50B, a first pilot pressure sensor 70A and a second pilot pressure sensor 70B (an example of a pilot pressure detection unit), a swivel speed sensor 80 (an example of a swirl speed detection unit), and a controller 90. ..

The hydraulic pump 10 discharges hydraulic oil for operating the swivel motor 20. The pilot pump 11 discharges pilot oil for supplying pilot pressure to the swirl control valve 40. Each of the hydraulic pump 10 and the pilot pump 11 is driven by the engine 12. Specifically, in the present embodiment, the hydraulic pump 10 is a variable displacement hydraulic pump in which the pump capacity can be adjusted. The hydraulic pump 10 has a regulator (not shown). The regulator operates so as to change the pump capacity to a capacity corresponding to the capacity command signal by receiving an input of a capacity command signal from the controller 90.

The swivel motor 20 operates so as to swivel the upper swivel body 2 in response to the supply of the hydraulic oil discharged from the hydraulic pump 10. Specifically, the swivel motor 20 has an output shaft that rotates in response to the supply of the hydraulic oil. The output shaft is connected to the upper swivel body 2 so as to swivel the upper swivel body 2 in both left and right directions. The swivel motor 20 has a first port 20A and a second port 20B on the opposite side thereof. When one of these ports 20A and 20B receives the supply of the hydraulic oil, the output shaft rotates in the direction corresponding to the one port, and the hydraulic oil is discharged from the other port.

The swivel control valve 40 is interposed between the hydraulic pump 10 and the swivel motor 20 and operates so as to change the direction and flow rate of the hydraulic oil supplied from the hydraulic pump 10 to the swivel motor 20. .. Specifically, in the present embodiment, the swivel control valve 40 is a pilot switching valve at three positions. The swivel control valve 40 is displaced according to the pilot pressure of the pilot oil supplied to the first swivel pilot port 40A and the second swivel pilot port 40B and any one of the swivel pilot ports 40A and 40B. It has a spool of illustrations possible. The pilot pressure changes according to the operation amount of the turning operation (the amount of operation received by the turning operation lever 31 described later), which is the operation for operating the turning motor 20.

The swivel control valve 40 is connected to the first port 20A of the swivel motor 20 via the first line L11, and is connected to the second port 20B of the swivel motor 20 via the second line L12. Has been done. The swivel control valve 40 uses the hydraulic oil discharged from the hydraulic pump 10 by the displacement of the spool in response to the pilot pressure to the first port 20A and the second port 20B of the swivel motor 20. Selectively lead to one side. As a result, the direction of the hydraulic oil supplied to the swivel motor 20 is controlled. Further, in the swivel control valve 40, the size of the opening on the meter-in side (opening area) and the size of the opening on the meter-out side (opening) of the swivel control valve 40 due to the displacement of the spool according to the pilot pressure. It opens and closes to change the area). The size of the opening on the meter-in side and the size of the opening on the meter-out side increase as the pilot pressure input to the swivel pilot port increases. As a result, the flow rate of the hydraulic oil supplied to the swivel motor 20 is controlled.

More specifically, the spool of the swivel control valve 40 is in the neutral position when the pilot pressures supplied to the first and second swivel pilot ports 40A and 40B are both zero or minute. Be kept. As a result, the center line L1 connected to the discharge port of the hydraulic pump 10 and the swivel motor 20 are cut off, and the center line L1 and the tank are connected. On the other hand, when the spool of the swivel control valve 40 is supplied with a pilot pressure equal to or higher than a certain level to any one of the first and second swivel pilot ports 40A and 40B, the spool is piloted in a direction corresponding to the pilot port. It is displaced from the neutral position with a stroke according to the magnitude of pressure. As a result, the turning supply line L2 branching from the center line L1 and one of the first line L11 and the second line L12 are connected, and the degree corresponding to the stroke is increased. The center line L1 is narrowed down.

The swivel operation device 30 includes a swivel operation lever 31 (an example of a swivel operation member) and a swivel pilot valve 32 (remote control valve). The swivel operation lever 31 is a member capable of rotating in response to a swivel operation by an operator for operating the swivel motor 20. The swivel pilot valve 32 is interposed between the pilot pump 11 and the first and second swivel pilot ports 40A and 40B in the swivel control valve 40, and corresponds to the amount of operation of the swivel operation by the operator. Output pilot pressure. Specifically, the swivel pilot valve 32 has the pilot pump 11 and the first and second swivel pilot ports 40A and 40B when the swivel operation lever 31 is not operated and the lever position is in the neutral position. The valve is closed so as to shut off the gap. On the other hand, when the swivel operation is performed and the swivel operation lever 31 rotates from the neutral position, the swivel pilot valve 32 has the direction of the swivel operation among the first and second swivel pilot ports 40A and 40B. The valve is opened so as to supply a pilot pressure of a magnitude corresponding to the operation amount of the turning operation to the turning pilot port corresponding to the above.

The first pressure reducing valve 50A is interposed between the swivel pilot valve 32 and the first swivel pilot port 40A. The first pressure reducing valve 50A reduces the pilot pressure output from the turning pilot valve 32 to the pilot pressure corresponding to the pressure reducing command signal by receiving the input of the pressure reducing command signal, and the turning control valve 40. It is possible to operate so as to input to the first swivel pilot port 40A in the above. The second pressure reducing valve 50B is interposed between the swivel pilot valve 32 and the second swivel pilot port 40B. The second pressure reducing valve 50B reduces the pilot pressure output from the turning pilot valve 32 to the pilot pressure corresponding to the pressure reducing command signal by receiving the input of the pressure reducing command signal, and the turning control valve 40. It is possible to operate so as to input to the second turning pilot port 40B in the above.

Specifically, in the present embodiment, each of the first and second pressure reducing valves 50A and 50B is composed of a solenoid valve having a solenoid 50S. Each of the first and second pressure reducing valves 50A and 50B corresponds to the pilot pressure input from the swivel pilot valve 32 and a pressure reducing command signal which is an electric signal input from the controller 90 to the solenoid 50S. It is configured to be able to reduce the pressure to the pilot pressure. The pilot pressure reduced in the first pressure reducing valve 50A, that is, the secondary pressure of the first pressure reducing valve 50A is input to the first swivel pilot port 40A. The pilot pressure reduced in the second pressure reducing valve 50B, that is, the secondary pressure of the second pressure reducing valve 50B is input to the second swivel pilot port 40B. In the present embodiment, each of the first and second pressure reducing valves 50A and 50B is composed of an electromagnetic inverse proportional valve, but may be composed of, for example, an electromagnetic proportional valve.

Each of the first and second pilot pressure sensors 70A and 70B is composed of a pressure sensor capable of detecting the pilot pressure output from the swivel pilot valve 32. The first pilot pressure sensor 70A detects the pressure of the pilot oil supplied from the swivel pilot valve 32 to the first pressure reducing valve 50A, and converts this into a pilot pressure detection signal which is an electric signal. The second pilot pressure sensor 70B detects the pressure of the pilot oil supplied from the swivel pilot valve 32 to the second pressure reducing valve 50B, and converts this into a pilot pressure detection signal which is an electric signal. These pilot pressure detection signals are input to the controller 90.

The turning speed sensor 80 is composed of a sensor capable of detecting the rotation speed of the turning motor 20 as a turning speed. The turning speed sensor 80 detects the turning speed and converts it into a turning speed detection signal which is an electric signal. The turning speed detection signal is input to the controller 90. Specifically, the turning speed sensor 80 detects the magnitude and turning direction of the detected turning speed of the upper turning body 2 and converts it into the turning speed detection signal. The turning speed detection signal is input to the controller 90. As the turning speed sensor 80, for example, a sensor such as a gyro sensor, an encoder, or a resolver can be used, but the turning speed sensor 80 is not limited thereto.

The swivel control device includes a relief valve line L21, a pair of relief valves 61A and 61B provided on the relief valve line L21, a check valve line L22, and a pair of check valves 62A provided on the check valve line L22. , 62B, a connection line L23, and a make-up line L24. Each of the relief valve line L21 and the check valve line L22 bypasses the swivel motor 20 and connects the first line L11 and the second line L12 to each other. The connection line L23 connects the intermediate portion between the pair of relief valves 61A and 61B in the relief valve line L21 and the intermediate portion between the pair of check valves 62A and 62B in the check valve line L22 to each other. To do. The intermediate portion of the check valve line L22 is connected to the tank via the make-up line L24. The make-up line L24 may be provided with a back pressure valve (not shown). Of the pair of check valves 62A and 62B, one check valve 62A is arranged in a direction to prevent the inflow of hydraulic oil from the first line L11, and the other check valve 62B is the second line. It is arranged so as to prevent the inflow of hydraulic oil from L12.

In the swivel control device, the swivel control valve 40 opens the meter-out side of the swivel control valve 40 as the pilot pressure supplied to the first or second swivel pilot port 40A or 40B decreases. Operates so that the size (opening area) of the Therefore, when the pilot pressure supplied to the swivel pilot port becomes small during the swivel operation of the upper swivel body 2, the pressure on the meter-out side of the first line L12 and the second line L12 (Back pressure) rises. As a result, a hydraulic braking action that reduces the turning speed of the upper turning body 2 is generated in the turning motor 20, so that the turning speed of the upper turning body 2 is gradually reduced. During such deceleration of turning, the pair of relief valves 61A and 61B are on the meter-out side of the first line L11 and the second line L12 due to the inertial force of the upper turning body 2. Protect the hydraulic circuit by preventing excessive pressure on the line. Further, when the rotation is decelerated, the pair of check valves 62A and 62B exceed the rotation speed corresponding to the amount of hydraulic oil supplied from the hydraulic pump 10 due to the inertial force of the upper swing body 2. Cavitation caused by the rotation of the swivel motor 20 at the rotation speed is prevented.

FIG. 3 is a block diagram showing a functional configuration of the controller 90 in the turning control device and its input / output signals. The controller 90 is composed of a computer having a CPU, a ROM for storing various control programs, and a RAM used as a work area of the CPU. The controller 90 includes a deceleration operation determination unit 91, a pilot pressure calculation unit 92, and a decompression signal input unit 93 as functions.

The deceleration operation determination unit 91 performs a deceleration operation, which is an operation for reducing the turning speed of the upper swivel body 2, based on the pilot pressure detected by the pilot pressure sensors 70A and 70B. Determines whether or not it has been received.

The pilot pressure calculation unit 92 has a braking action pilot pressure for causing a hydraulic braking action in the turning motor 20 when the upper turning body 2 is turning at the turning speed detected by the turning speed sensor 80. Is calculated. The braking action pilot pressure is a pilot pressure for adjusting the size of the opening on the meter-out side of the turning control valve 40 so that the hydraulic braking action occurs.

The decompression signal input unit 93 uses the pilot pressure output from the swivel pilot valve 32 as the braking action pilot pressure when the deceleration operation determination unit 91 determines that the swivel operation lever 31 has undergone the deceleration operation. A decompression command signal for depressurizing is input to the solenoid 50S of the pressure reducing valve corresponding to the direction in which the swivel operating lever 31 is tilted among the pair of pressure reducing valves 50A and 50B.

Hereinafter, the operation of the turning control device according to the present embodiment and the operation of the turning control device according to the comparative example will be described.

FIG. 4 is a graph showing a time-dependent change in the pilot pressure (swinging Pi pressure) output from the swirling pilot valve 32 and a time-dependent change in the swirling speed of the upper swivel body 2. The pilot pressure in FIG. 4 is the pilot pressure detected by the pilot pressure sensor corresponding to the direction of the turning operation among the first and second pilot pressure sensors 70A and 70B. Further, in FIG. 4, the change with time of the turning speed in the turning control device according to the present embodiment is shown by a solid line, and the change with time of the turning speed in the turning control device according to the comparative example is shown by a broken line.

As shown in FIG. 4, at the time t0, the turning operation by the operator is started from the state where the turning operation lever 31 is arranged in the neutral position. In the turning operation, the turning operation lever 31 is tilted in the direction of the turning operation corresponding to either the right turning direction or the left turning direction. When the turning operation is started, the amount of operation received by the turning operation lever 31, that is, the tilt angle of the turning operation lever 31 is continuously and gradually increased from the time t0 to the time t2. The tilting operation of the turning operation lever 31 is stopped at the time t2, and the operating amount of the turning operating lever 31 is held in the operating amount LM from the time t2 to the time t3. In the specific example shown in FIG. 4, the operation amount LM in the time zone from the time t2 to the time t3 is the maximum corresponding to the maximum tilt position in which the swivel operation lever 31 can be tilted in the direction of the swivel operation. The operation amount is LM (so-called full lever). Then, at the time t3, the return operation, which is the operation of the turning operation lever 31 so that the turning operation lever 31 approaches the neutral position side from the maximum tilting position, is started. When the return operation is started, the operation amount of the turning operation continuously and gradually decreases from the time t3 to the time t7, and becomes zero at the time t7.

As shown in FIG. 4, the swivel pilot valve 32 outputs a pilot pressure according to the operation amount of the swivel operation during the time t0 to the time t7. Specifically, the pilot pressure output from the swivel pilot valve 32 increases with an increase in the amount of operation from the time t0, reaches the pilot pressure PM at the time t2, and starts from the time t2. The pilot pressure PM is maintained until the time t3. Then, the pilot pressure output from the swivel pilot valve 32 decreases from the time point of the time t3 as the operation amount decreases, and becomes zero or the minimum value at the time point of the time t7. In the specific example shown in FIG. 4, the pilot pressure PM between the time t2 and the time t3 is the maximum pilot pressure PM corresponding to the maximum manipulated variable LM.

As shown in FIG. 4, the turning speed of the upper turning body 2, that is, the turning speed detected by the turning speed sensor 80, gradually increases from the time t0 when the turning operation is started. The maximum speed VM has not been reached at the time t2 when the operation amount of the turning operation reaches the maximum operation amount LM. Then, in the specific example shown in FIG. 4, the return operation is started before the turning speed reaches the maximum speed VM, and the turning speed gradually decreases due to the hydraulic braking action without reaching the maximum speed VM. To do. In the present embodiment shown by the solid line in FIG. 4, the turning speed becomes zero at the time t8, and in the comparative example shown by the broken line in FIG. 4, the turning speed is the time t9 after the time t8. It becomes zero at that point. The reason why the time required for the turning operation to stop is different between the present embodiment and the comparative example will be described.

At the time t3 when the return operation is started, the operation amount of the turning operation lever 31 is the maximum operation amount LM, and the pilot pressure output by the turning pilot valve 32 is the maximum pilot pressure PM. The size of the opening on the meter-out side of the swing control valve 40 is the maximum opening area. On the other hand, at the time t3, the turning speed is smaller than the maximum speed VM. Therefore, the flow rate of the hydraulic oil discharged from the swing motor 20 and flowing through the meter-out side line L11 or L12 at the time t3 is a relatively small flow rate corresponding to the swing speed at the time t3. Become. Therefore, at the time t3 when the return operation is started, the back pressure on the meter-out side does not sufficiently increase, so that the hydraulic braking action that reduces the turning speed of the upper swing body 2 does not substantially occur. .. Therefore, as shown in FIG. 4, the turning speed of the upper turning body 2 increases due to inertia even after the time t3.

Specifically, in the comparative example, the turning speed further increases from the time t3 to the time t6 to reach the speed Ve, and the flow rate of the hydraulic oil flowing through the meter-out side line L11 or L12 increases, while the above-mentioned The operation amount of the swivel operation lever 31 continuously decreases from the time t3 to the time t6, and the size of the opening on the meter-out side also continuously decreases. Then, in the comparative example, at the time t6, the back pressure on the meter-out side rises to the extent that the hydraulic braking action is generated. After this time t6, the turning speed slightly increases due to inertia, but then begins to decrease and becomes zero at the time t9.

In this comparative example, the time zone T2 from the time t3 to the time t6 is a dead zone in which the hydraulic braking action does not substantially occur even though the return operation is started. In this comparative example, the time t6 at which the hydraulic braking action starts varies according to the turning speed at the time t3 when the return operation is started, so that the size of the time zone T2 also depends on the time t6. Fluctuates. That is, the time point (brake point) at the time t6 is a value that fluctuates each time the return operation is performed. This makes it difficult to accurately stop the attachment 3 at the target position. As a result, extra work is required to correct the position of the attachment.

On the other hand, in the present embodiment, when the deceleration operation determination unit 91 determines that the turning operation lever 31 has undergone the deceleration operation at the time t5, the decompression signal input unit 93 transmits the decompression command signal. Input to the corresponding pressure reducing valve 50A or 50B. As a result, the pilot pressure output from the swivel pilot valve 32 is reduced to the braking pilot pressure at the pressure reducing valve 50A or 50B, and the braking pilot pressure is input to the swivel control valve 40. As a result, the size of the opening on the meter-out side of the swivel control valve 40 is adjusted to a size corresponding to the braking action pilot pressure, so that when the upper swivel body 2 is swiveling at the swivel speed. The hydraulic braking action can be generated in the swivel motor 20. Specifically, it is as follows.

In the present embodiment, the first pilot pressure threshold value Pi1 and the second pilot pressure threshold value Pi2 for determining the deceleration operation are set in advance, and these threshold values Pi1 and Pi2 are stored in the memory of the controller 90. ing.

The first pilot pressure threshold value Pi1 is set to determine whether or not the operation amount of the turning operation is the maximum operation amount LM or whether or not the operation amount is close to the maximum operation amount LM. It is a threshold. Therefore, as shown in FIG. 4, the first pilot pressure threshold value Pi1 is set to a value close to the maximum pilot pressure PM or the maximum pilot pressure PM corresponding to the maximum manipulated variable LM. Specifically, in the present embodiment, the first pilot pressure threshold value Pi1 is a value smaller than the maximum pilot pressure PM and is larger than a value of 1/2 of the maximum pilot pressure PM. It is set to a value close to the pressure PM.

The second pilot pressure threshold value Pi2 means that the operation amount of the turning operation is reduced from the maximum operating amount LM, that is, the turning operation lever 31 operates from the maximum tilting position to the neutral position. It is a threshold value set to determine that. Therefore, as shown in FIG. 4, the second pilot pressure threshold value Pi2 is set to a value smaller than the first pilot pressure threshold value Pi1. Specifically, in the present embodiment, the second pilot pressure threshold value Pi2 is set to a value closer to the first pilot pressure threshold value Pi1 than a value of 1/2 of the maximum pilot pressure PM.

In the deceleration operation determination unit 91, after the pilot pressure detected by the pilot pressure sensor 70A or 70B becomes equal to or higher than the first pilot pressure threshold value Pi1, the pilot pressure detected by the pilot pressure sensor is the pilot pressure. When it becomes less than the second pilot pressure threshold value Pi2, it is determined that the turning operation lever 31 has undergone the deceleration operation. In the specific example shown in FIG. 4, the pilot pressure detected by the pilot pressure sensor 70A or 70B becomes equal to or higher than the first pilot pressure threshold value Pi1 at the time t1 and the second pilot at the time t5. The pressure threshold is less than Pi2. Therefore, the deceleration operation determination unit 91 determines that the turning operation lever 31 has received the deceleration operation at the time t5.

When it is determined that the turning operation lever 31 has undergone the deceleration operation, the pilot pressure calculation unit 92 calculates the braking action pilot pressure (target secondary pressure) based on the turning speed. The calculation of the braking action pilot pressure is performed based on, for example, the maps shown in FIGS. 5 and 6.

FIG. 5 shows the turning speed of the upper turning body 2 and the turning control valve 40 capable of causing the hydraulic braking action in the turning motor 20 when the upper turning body 2 is turning at the turning speed. This is an example of a map showing the relationship between the size of the opening on the meter-out side (swivel MO opening area) in. FIG. 6 is a graph showing the relationship between the size of the opening on the meter-out side (swivel MO opening area) and the target secondary pressure in the pressure reducing valve (inverse proportional valve) of the swivel control device. The maps shown in the graphs of FIGS. 5 and 6 are preset and stored in the memory of the controller 90, respectively.

In the following, the time when the deceleration operation determination unit 91 determines that the turning operation lever 31 has undergone the deceleration operation may be referred to as "at the time of deceleration determination", and the turning speed sensor 80 at the time of the deceleration determination. The turning speed detected by the above may be referred to as "turning speed at the time of deceleration determination".

As shown in FIG. 5, when the turning speed at the time of deceleration determination is, for example, a speed Va, the size of the opening on the meter-out side capable of causing the hydraulic braking action at the turning speed Va is the opening area. The opening area is less than or equal to Ka. Further, when the turning speed at the time of the deceleration determination is, for example, a speed Vb smaller than the speed Va, the size of the opening on the meter-out side capable of causing the hydraulic braking action at the turning speed Vb is the above. The opening area is smaller than the opening area Ka and is less than or equal to the opening area Kb.

That is, when the turning speed at the time of the deceleration determination is relatively large, the hydraulic braking action occurs at the lever position where the operating amount of the turning operation lever 31 (tilting angle of the turning operation lever 31) is relatively large, and the hydraulic braking action occurs. The brake starts to be applied to the turning operation of the upper turning body 2. On the other hand, when the turning speed at the time of the deceleration determination is small, in order to cause the hydraulic braking action, the turning operation lever 31 is returned to the lever position where the operation amount of the turning operation lever 31 is small, so that the meter out. The opening area of the side opening needs to be reduced.

In the present embodiment, at the time t3 when the return operation is started, the back pressure on the meter-out side does not sufficiently increase, so that a hydraulic braking action that reduces the turning speed of the upper swing body 2 occurs. Absent. Therefore, as shown in FIG. 4, the turning speed of the upper turning body 2 increases due to inertia even after the time t3. Further, even at the time point of the time t5, which is the time of the deceleration determination, the back pressure on the meter-out side is not sufficiently increased, so that the hydraulic braking action for reducing the turning speed of the upper swing body 2 does not occur.

However, in the present embodiment, when the deceleration operation determination unit 91 determines that the turning operation lever 31 has undergone the deceleration operation at the time t5, the pilot pressure calculation unit 92 causes the turning at that time. The braking action pilot pressure is calculated based on the speed. Specifically, when the turning speed at the time of deceleration determination is, for example, a speed Va, the pilot pressure calculation unit 92 has a size of the opening on the meter-out side corresponding to the speed Va based on the map shown in FIG. The opening area Ka, which is the speed, is calculated. Next, the pilot pressure calculation unit 92 calculates the target secondary pressure Pa of the pressure reducing valve corresponding to the opening area Ka, that is, the braking action pilot pressure Pa, based on the map shown in FIG.

FIG. 7 shows the relationship between the target secondary pressure in the pressure reducing valve and the pressure reducing command signal (instructed current) to be input to the pressure reducing valve in order to adjust the secondary pressure in the pressure reducing valve to the target secondary pressure. It is a graph which shows. When the braking action pilot pressure Pa is calculated, the decompression signal input unit 93 reduces the pilot pressure output from the swivel pilot valve 32 to the braking action pilot pressure Pa based on the map shown in FIG. The decompression command signal Ca, which is such a current value, is calculated, and the decompression command signal is input to the solenoid 50S of the corresponding pressure reducing valve among the pair of pressure reducing valves 50A and 50B.

When the turning speed at the time of the deceleration determination is the speed Vb, the pilot pressure calculation unit 92 determines the size of the opening on the meter-out side corresponding to the speed Vb based on the map shown in FIG. A certain opening area Kb is calculated, a braking action pilot pressure Pb corresponding to the opening area Kb is calculated based on the map shown in FIG. 6, and the decompression signal input unit 93 calculates a decompression command based on the map shown in FIG. The signal Cb is calculated, and the pressure reducing command signal Cb is input to the solenoid 50S of the pressure reducing valve.

As a result, the pilot pressure output from the swivel pilot valve 32 is reduced to the braking pilot pressure Pa (or Pb) at the pressure reducing valve 50A or 50B, and the braking pilot pressure Pa (or Pb) is swiveled. It is input to the control valve 40. As a result, the size of the opening on the meter-out side of the swivel control valve 40 is adjusted to a size corresponding to the braking action pilot pressure Pa (or Pb), so that the upper swivel body 2 has the swivel speed Va. The hydraulic braking action can be generated in the turning motor 20 when turning at (or Vb). This makes it possible for the swivel motor 20 to quickly generate the hydraulic braking action regardless of the magnitude of the swivel speed at the time of the deceleration determination. As a result, it is possible to prevent variations in the time required for the brake to start working in the deceleration operation regardless of the magnitude of the turning speed at the time of the deceleration determination. This makes it possible to realize a stable turning deceleration operation and a turning stop operation, and makes it possible to improve the workability of the turning work.

In this embodiment, the time zone T1 from the time t3 to the time t5 is a dead zone in which the hydraulic braking action does not substantially occur even though the return operation is started. In this embodiment, the time t5 at which the hydraulic braking action starts does not fluctuate according to the turning speed at the time t3 when the return operation is started, and the preset second pilot It is determined based on the pressure threshold value Pi2. Therefore, the size of the time zone T1 does not change according to the turning speed at the time t3 when the return operation is started, and is determined based on the second pilot pressure threshold value Pi2 set in advance. As a result, the brake point (at the time point of the time t5) is suppressed from fluctuating as in the comparative example.

Next, a specific operation performed by the controller 90 in the turning control device according to the present embodiment will be described with reference to the flowchart of FIG.

FIG. 8 is a flowchart showing an arithmetic control operation of the controller 90 in the turning control device according to the present embodiment. First, the deceleration operation determination unit 91 of the controller 90 determines whether or not the turning operation lever 31 has undergone the deceleration operation. The deceleration operation determination unit 91 determines the deceleration operation, for example, based on the processes shown in steps S1 to S9 of FIG. Specifically, it is as follows.

The deceleration operation determination unit 91 acquires the pilot pressure (swivel Pi pressure) detected by the pilot pressure sensors 70A and 70B (step S1). Next, in the deceleration operation determination unit 91, among the pilot pressure sensors 70A and 70B, the pilot pressure detected by the pilot pressure sensor corresponding to the direction of the turning operation is equal to or higher than the first pilot pressure threshold value Pi1. Whether or not it is determined (step S2). As shown in FIG. 4, when the pilot pressure becomes equal to or higher than the first pilot pressure threshold value Pi1 at the time t1, the deceleration operation determination unit 91 detects the pilot pressure by the pilot pressure sensor 70A or 70B. Is determined to be equal to or higher than the first pilot pressure threshold value Pi1 (YES in step S2), the full lever flag is set to ON, and the brake flag is set to OFF (step S3).

Next, the deceleration operation determination unit 91 determines whether or not the brake flag is OFF (step S4). Immediately after the brake flag is set to OFF in step S3, the setting of the brake flag is maintained as OFF, so that the deceleration operation determination unit 91 determines that the brake flag is OFF. (YES in step S4).

Next, the deceleration operation determination unit 91 determines whether or not the setting of the full lever flag has been switched from ON to OFF (step S5). Immediately after the full lever flag is set to ON in step S3, the setting of the full lever flag is maintained as ON, so that the deceleration operation determination unit 91 sets the full lever flag to ON. Is not switched to OFF (NO in step S5). In such a case, the pressure reducing signal input unit 93 does not input the pressure reducing command signal to the pressure reducing valve (step S6). Specifically, in the present embodiment, since each of the pressure reducing valves 50A and 50B is composed of an electromagnetic inverse proportional valve, the pressure reducing signal input unit 93 is the direction of the turning operation of the pressure reducing valves 50A and 50B. The pressure reducing valve corresponding to the above inputs a command signal (for example, a signal corresponding to the minimum current value) output from the swivel pilot valve 32 to the pressure reducing valve so as not to reduce the pressure of the pilot pressure (step S6).

Next, the deceleration operation determination unit 91 reacquires the pilot pressure detected by the pilot pressure sensors 70A and 70B (step S1), and in the direction of the turning operation among the pilot pressure sensors 70A and 70B. It is determined again whether or not the pilot pressure detected by the corresponding pilot pressure sensor is equal to or higher than the first pilot pressure threshold value Pi1 (step S2). The deceleration operation determination unit 91 determines that the pilot pressure is not equal to or higher than the first pilot pressure threshold value Pi1 at the time t4 (NO in step S2). Further, the deceleration operation determination unit 91 determines that the pilot pressure is less than the second pilot pressure threshold value Pi2 at the time t5 (YES in step S7), and sets the full lever flag to OFF. (Step S8).

Next, the deceleration operation determination unit 91 again determines whether or not the brake flag is OFF (step S4). When the setting of the brake flag is maintained OFF in step S3, the deceleration operation determination unit 91 determines that the brake flag is OFF (YES in step S4).

Next, the deceleration operation determination unit 91 determines whether or not the setting of the full lever flag has been switched from ON to OFF (step S5). In the present embodiment, at the time t5, the deceleration operation determination unit 91 determines that the setting of the full lever flag has been switched from ON to OFF (YES in step S5). In such a case, the deceleration operation determination unit 91 determines that the turning operation lever 31 has received the deceleration operation, and sets the brake flag to ON (step S9).

Next, the pilot pressure calculation unit 92 calculates the braking action pilot pressure based on the turning speed at the time of the deceleration determination. The calculation of the braking action pilot pressure by the pilot pressure calculation unit 92 is performed, for example, based on the process shown in steps S10 to S12 of FIG. First, the pilot pressure calculation unit 92 acquires the turning speed at the time of the deceleration determination from the turning speed sensor 80 (step S10). Next, the pilot pressure calculation unit 92 determines the size (opening area) of the opening (MO opening) on the meter-out side capable of causing the hydraulic braking action at the turning speed at the time of deceleration determination, for example. The calculation is performed based on the map shown in 5 (step S11). Next, the pilot pressure calculation unit 92 calculates the braking action pilot pressure (target Pi pressure) corresponding to the opening area based on, for example, the map shown in FIG. 6 (step S12).

Next, the decompression signal input unit 93 calculates a decompression command signal based on, for example, the map shown in FIG. 7, and inputs the decompression command signal to the solenoid 50S of the pressure reducing valve 50A or 50B (inverse proportional valve). (Step S13). As a result, the pilot pressure output from the swivel pilot valve 32 is reduced to the braking pilot pressure at the pressure reducing valve 50A or 50B, and the braking pilot pressure is input to the swivel control valve 40. As a result, the size of the opening on the meter-out side of the swivel control valve 40 is adjusted to a size corresponding to the braking action pilot pressure, so that the swivel motor 20 hydraulically moves at the swivel speed at the time of the deceleration determination. A braking action can be generated.

The processing after the step S13 in FIG. 8 is performed is not particularly limited, and the following aspects can be exemplified. The deceleration operation determination unit 91 reacquires the pilot pressure detected by the pilot pressure sensors 70A and 70B (step S1), and the pilot pressure detected by the pilot pressure sensor is the first pilot pressure threshold value Pi1. It is determined again whether or not it is the above (step S2). The deceleration operation determination unit 91 determines that the pilot pressure is not equal to or higher than the first pilot pressure threshold value Pi1 (NO in step S2) at a time point after the time t5, and the pilot pressure is the second pilot pressure. It is determined that the value is less than the pilot pressure threshold value Pi2 (YES in step S7), and the setting of the full lever flag is kept OFF (step S8).

Next, the deceleration operation determination unit 91 again determines whether or not the brake flag is OFF (step S4). Since the setting of the brake flag is maintained ON at a time after the time t5, the deceleration operation determination unit 91 determines that the brake flag is not OFF (NO in step S4).

Next, the pilot pressure calculation unit 92 calculates the braking action pilot pressure based on the turning speed at a time point after the time t5. The calculation of the braking action pilot pressure by the pilot pressure calculation unit 92 is performed, for example, based on the process shown in steps S10 to S12 of FIG. As a result, even at a time point after the time t5, the pilot pressure output from the swivel pilot valve 32 is reduced to the braking pilot pressure at the pressure reducing valve 50A or 50B, and the braking pilot pressure becomes the swivel. It is input to the control valve 40. As a result, the size of the opening on the meter-out side of the swivel control valve 40 is adjusted to a size corresponding to the braking action pilot pressure, so that the swivel motor at a swivel speed at a time point after the time t5. At 20, the hydraulic braking action can be continuously generated.

The present invention is not limited to the embodiments described above. The present invention can include, for example, the following aspects.

(A) Processing after deceleration determination In the embodiment, at the time t5 shown in FIG. 4 (at the time of deceleration determination), the decompression signal input unit 93 sends the decompression command signal to the pressure reducing valve 50A or 50B. The process of inputting to the solenoid 50S (step S13) and after the time t5 is repeated again in steps S1 to S13 of FIG. 8, but the present invention is not limited to this. In the present invention, as the process after the time t5, a process different from the process of steps S1 to S13 of FIG. 8 may be adopted. Specifically, after the decompression signal input unit 93 inputs the decompression command signal to the solenoid 50S of the decompression valve at the time point t5 shown in FIG. 4 (at the time of the deceleration determination), the decompression signal input unit 93 Even if a map having a characteristic that the target secondary pressure of the pressure reducing valve is gradually reduced is set and a command signal calculated based on the map is input to the solenoid 50S of the pressure reducing valve. Good. In the map, for example, the braking action pilot pressure Pa (or Pb) at the time point t5 (at the time of deceleration determination) and the pilot pressure Pc smaller than the braking action pilot pressure Pa are connected by a straight line or a curved line. It may be generated by. The pilot pressure Pc may be, for example, a pilot pressure such that the spool of the swivel control valve 40 is arranged in a neutral position, or when the opening on the meter-out side of the swivel control valve 40 begins to open. It may be pilot pressure.

Further, after the pressure reducing signal input unit 93 inputs the pressure reducing command signal to the solenoid 50S of the pressure reducing valve at the time point t5 shown in FIG. 4 (at the time of the deceleration determination), the pressure of the pilot pressure is reduced by the pressure reducing valve. If the hydraulic braking action occurs even if it is not performed, the decompression signal input unit 93 sends a command signal for depressurizing the pilot pressure output from the swivel pilot valve after the time t5. It is not necessary to input to the pressure reducing valve.

(B) Determination of deceleration operation In the above embodiment, the deceleration operation determination unit 91 determines the deceleration operation by the processes of steps S1 to S9 shown in FIG. 8, but the present invention is not limited to this. .. In the present invention, the first pilot pressure threshold value may be omitted in the determination of the deceleration operation, and the determination of the deceleration operation may be performed based only on the second pilot pressure threshold value. That is, when the pilot pressure detected by the pilot pressure detection unit becomes less than a preset pilot pressure threshold value (threshold value corresponding to the second pilot pressure threshold value), the deceleration operation determination unit said. It may be determined that the turning operation member has undergone the deceleration operation.

(C) Operation amount at the time of deceleration determination In the embodiment, the first pilot pressure threshold value Pi1 is set to a value capable of determining whether or not the operation amount of the turning operation is the maximum operation amount. However, the present invention is not limited to this. In the present invention, for example, the first pilot pressure threshold value is set to a value capable of determining whether or not the operation amount of the turning operation is an operation amount smaller than the maximum operation amount (for example, a so-called half lever). It may have been done.

(D) Types of Construction Machines In the above embodiment, the construction machine is a hydraulic excavator, but the construction machine equipped with the swivel control device of the present invention is not limited to the hydraulic excavator, such as a swivel crane. It may be another construction machine. Further, the tip attachment is not limited to a bucket, and may be another tip attachment such as a grapple, a crusher, a breaker, or a fork.

(E) Regarding the substrate In the above embodiment, the lower traveling body 1 is used as the substrate, but the substrate is not limited to the one that can travel like the lower traveling body 1, and is installed at a specific place and has an upper portion. It may be a base that supports the swivel body 2.

1 Lower traveling body 2 Upper swivel body 10 Hydraulic pump 20 Swing motor 30 Swivel operation device 31 Swivel operation lever (example of swivel operation member)
32 Swing pilot valve 40 Swing control valve 50A First pressure reducing valve 50B Second pressure reducing valve 70A, 70B Pilot pressure sensor (an example of pilot pressure detection unit)
80 Turning speed sensor (an example of turning speed detection unit)
90 Controller 91 Deceleration operation judgment unit 92 Pilot pressure calculation unit 93 Decompression signal input unit 100 Construction machinery Ca, Cb Decompression command signal Ka, Kb The size of the opening on the meter-out side of the swivel control valve (opening area)
LM maximum operating amount (an example of operating amount of turning operation member)
PM maximum pilot pressure Pa, Pb Brake action pilot pressure (secondary pressure of pressure reducing valve)
Pi1 1st pilot pressure threshold Pi2 2nd pilot pressure threshold Va, Vb, VM turning speed

Claims (3)

A swivel control device for construction machinery provided with an upper swivel that can swivel with respect to the substrate.
A hydraulic pump that discharges hydraulic oil and
A swivel motor that operates to swivel the upper swivel body by receiving the supply of the hydraulic oil discharged from the hydraulic pump, and
A swivel operation device having a swivel operation member that receives a swivel operation, which is an operation for operating the swivel motor, and a swivel pilot valve that outputs a pilot pressure according to the operation amount of the swivel operation.
A swivel control valve interposed between the hydraulic pump and the swivel motor so as to change the size of the opening on the meter-out side according to the pilot pressure input from the swivel pilot valve to the swivel control valve. With a swivel control valve that opens and closes
A swivel speed detection unit that detects the swivel speed of the upper swivel body,
The size of the opening on the meter-out side so that the hydraulic braking action is generated by the braking action pilot pressure for causing the hydraulic braking action in the turning motor when the upper turning body is turning at the turning speed. A pilot pressure calculation unit that calculates the braking action pilot pressure for adjusting the speed based on the turning speed, and
A deceleration operation determination unit that determines whether or not the turning operation member has received a deceleration operation that is an operation for reducing the turning speed, and a deceleration operation determination unit.
A pressure reducing valve interposed between the swing pilot valve and the swing control valve, and the pilot pressure output from the swing pilot valve corresponds to the pressure reduction command signal by receiving an input of the pressure reduction command signal. A pressure reducing valve that can be operated to reduce the pressure to the pilot pressure and input it to the swing control valve.
When the deceleration operation determination unit determines that the swivel operation member has undergone the deceleration operation, the decompression command signal for reducing the pilot pressure output from the swivel pilot valve to the braking action pilot pressure is transmitted. A swivel control device for construction machinery including a pressure reducing signal input unit for inputting to a pressure reducing valve. The turning control device for a construction machine according to claim 1.
Further provided with a pilot pressure detecting unit for detecting the pilot pressure output from the swivel pilot valve.
The deceleration operation determination unit determines that the turning operation member has undergone the deceleration operation when the pilot pressure detected by the pilot pressure detection unit becomes less than a preset pilot pressure threshold value. Swivel control device. The turning control device for a construction machine according to claim 1.
Further provided with a pilot pressure detecting unit for detecting the pilot pressure output from the swivel pilot valve.
In the deceleration operation determination unit, after the pilot pressure detected by the pilot pressure detection unit becomes equal to or higher than a preset first pilot pressure threshold value, the pilot pressure detected by the pilot pressure detection unit is previously determined. When the set second pilot pressure threshold value becomes less than the second pilot pressure threshold value smaller than the first pilot pressure threshold value, it is determined that the turning operation member has undergone the deceleration operation. Machine swivel control device.

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